My aims for research during the coming five years include a number of different projects. One has to do with the characterization of enkephalin convertase, a carboxypeptidase which appears to be associated with the biosynthesis of enkephalin. We will try to measure the turnover of the enzyme and evaluate in detail its localization. Another project relates to angiotensin converting enzyme which can be labeled with the inhibitor H-3-captopril. We propose to attempt to identify what seems to be a novel neuropeptide which is the endoyenous substrate for this enzyme. We propose to localize endogenous adenosine and ascertain its possible neutrotransmitter role. We will continue studies of calcium antagonist receptors and their relationship to calcium flux in neurons. We will characterize biogenic amine uptake sites with a variety of ligands. We propose studies to further elucidate the function of sigma receptors which are associated with the psychotomimetic effects of opiates. We propose detailed investigations of phorbol ester receptors to clarify their relationship to protein kinase C in neuronal function. We will also evaluate the relationship of the receptor interactions fo neutoxin MPTP with monamine oxiuase.